With the assistance of Yale professor Oona A. Hathaway, Sen. Cory A. Booker (Democrat of New Jersey) has published an op-ed in The New York Times (“A Syria Plan that Breaks the Law”) accusing the Trump administration of wishing to wage war illegally in Syria, in a manner violating both the American Constitution and international law. Although the senator and his academic co-author make cogent points about the central role of Congress in declaring war and authorizing military operations, they risk inadvertently building a legal justification for consigning the people of eastern Syria to the ministrations of a homicidal regime in Damascus.No doubt Booker and Hathaway acknowledge that the fight against Daesh (ISIS) is not yet over in Syria east of the Euphrates River. Indeed, they make a key observation that is at the heart of the administration’s plans for the region in question: “Stabilizing the territory taken from the Islamic State is undoubtedly essential to ensuring terrorist threats do not re-emerge, and it must be a priority for the United States.”

In making such a statement, the authors separate themselves from many critics of the administration’s approach by demonstrating they understand a key point: A complex military operation (such as the three-year battle against Daesh) does not end until stability is restored to the territories taken from the enemy. As we have learned in Iraq in 2003 and Libya in 2011, this is not a disembodied piece of military doctrine or dogma.

The authors would have done their readers a further service had they focused their essay more on the components and end-state of a successful stabilization operation in eastern Syria. Instead they use imprecise language to describe when, in their view, the curtain comes down on stabilization operations and a residual American military presence becomes illegal: “after the Islamic State [Daesh] has been credibly debilitated;” “as the threat from the Islamic State diminishes ... .” Translating this sort of phraseology into language suitable for policy and plans is something the authors should have tried.

In addition to acknowledging the necessity of implementing post-combat stabilization measures to seal the forthcoming victory over Daesh, Booker and Hathaway take care to distance themselves from the Assad regime and its supporters. They deem the regime “repulsive” while asserting that “the role and intent of Russian and Iranian forces backing Assad remain of deep concern.”

More assertively, they argue that “the United States has a role to play in holding Mr. Assad accountable for the crimes he has committed against his own people and preventing him from committing more.”

Still, according to the authors, “an American-backed attempt to prevent it [the Assad regime] from re-establishing control over Syrian territory, as Secretary Rex Tillerson indicated, would embroil the United States in a new prolonged, bloody and increasingly complicated conflict.” Although one should not bet the farm on the survivability of Assad regime forces trying to ford the Euphrates River, let us take the alarmist rhetoric at face value. Should, therefore, a United States committed to stopping the Assad regime’s war crimes and crimes against humanity demonstrate its seriousness by stepping aside and permitting that regime to capitalize on the defeat of Daesh – a defeat in which it played no role – by occupying eastern Syria and expanding its crime wave at its leisure?

Indeed, if eastern Syria is to be successfully stabilized – “ensuring terrorist threats do not re-emerge” – then the Assad regime and the lawless, Iranian-led militias (featuring Shiite foreign fighters) must be excluded from the liberated territories indefinitely. If that exclusion is not an essential element of post-Daesh stabilization, then what has been the point of the past three years of combat? Surely Booker and Hathaway would acknowledge the truth of the assertion that the murderous, collective punishment policies of the Assad regime – enthusiastically supported by Russia and Iran – have pumped oxygen into the lungs of Islamist extremists and terrorists in Syria and around the world. Stabilize eastern Syria by turning it over to a regime that defines political illegitimacy and creates vacuums for other criminals to fill?

No doubt Booker would say that he gets it about Assad and the Iranians. But does he? The points he makes about the war-making role of Congress have plenty of merit. But if he really thinks that the stabilization of eastern Syria is necessary to prevent three years of war against Daesh from just swirling down the drain, and if he really believes that the United States should hold Assad accountable for his crimes and “[prevent] him from committing more,” will he work with the administration to find a bipartisan way forward on Syria? And will the administration be willing to work with senators Booker, Tim Kaine, and others?

The administration is on solid ground trying to seal the victory over Daesh and protect Americans from terrorism by stabilizing eastern Syria. Keeping a lawlessly brutal and corrupt Assad regime out of the liberated areas is, like it or not, an essential element of post-combat stabilization: No one in eastern Syria will want the fake caliph replaced by another mass murderer; one with disgusting addictions to chemical weaponry and torture. Rather than accusing the administration of contemplating its own brand of illegality, Booker and Hathaway might better put their excellent minds to squaring the circle of Congressional prerogatives with the protection of defenseless civilians in Syria.

Frederic C. Hof is director of the Atlantic Council's Rafik Hariri Center for the Middle East. This commentary is published by permission from the Atlantic Council and can be accessed at: http://www.atlanticcouncil.org/blogs/syriasource/response-to-senator-cory-booker-on-syria. A version of this article appeared in the print edition of The Daily Star on February 01, 2018, on page 7.